The present invention is directed toward stackable shipping containers and more particularly, toward wheeled trailer-like shipping containers which are also stackable and which can be towed directly by a truck.
Goods and merchandise of substantially all kinds are frequently shipped in large containers. This system, typically referred to as containerized freight utilizes closed box shaped containers capable of holding very large quantities of merchandise. The containers are frequently carried in the hold of a ship or on a barge or the like. At port, the containers can be transferred to a flatbed rail car or onto the flat bed of a truck trailer.
While the containers may vary slightly from each other, the majority of them are of substantially the same size and shape in accordance with I.S.O. standards promulgated by the International Standards Organization. As is well known in the art, each container has I.S.O. standard corner castings at the upper and lower eight corners thereof which allow the containers to be stacked and connected together and to be connected to the ship, rail car or trailer. Because the containers and corner castings are standardized, substantially any container, regardless of the manufacturer, can be carried by any ship, rail car or trailer and different containers can be connected together.
While the use of standardized containers is convenient and may save considerable time and expense, the final delivery of the merchandise still requires that the same either be off-loaded into the trailer of a tractor trailer for transport over land or the container can be loaded onto a flat bed trailer for such transport. Either system requires that a trailer be present at the dock or rail freight yard for transporting the containers.
It is, of course, theoretically possible to transport the trailers of tractor trailer trucks directly by ship or rail car. However, such trailers are not normally constructed to be sturdy enough for such transport. Furthermore, conventional trailers are not capable of being stacked and, therefore, would waste considerable space on a ship or rail car.
In addition to being used to ship merchandise and the like, such standardized shipping containers have recently been used to house portable operating machinery such as generators, power plants and the like. Thus, when a large generator is temporarily needed at a construction site, it can be delivered on a flat bed trailer. When not in use, the containerized power plant can be stacked with others for storage until needed and then shipped to the site. As with the containers used for shipping containerized freight, however, delivery of the containerized power plant requires the use of a trailer and truck tractor and additional equipment such as a heavy duty fork lift at the site for removing the container from the trailer. Otherwise, the trailer will also have to remain idle at the site.
The present invention is designed to overcome the deficiencies of the prior art discussed above. It is an object of the present invention to provide shipping containers which are trailer-like and are stackable.
It is another object of the present invention to provide shipping containers that can be stacked for transport on a rail car, ship or transport plane but which can also be pulled over the road by a standard tractor trailer.
In accordance with the illustrative embodiment demonstrating features and advantages of the present invention, there are provided shipping containers which are stackable and act as a trailer. Each of the stackable shipping trailers includes a substantially rectangularly shaped container having an interior capable of holding equipment or freight therein. The container is comprised essentially of two side walls, a front wall, a rear wall, a bottom wall and a top wall which form a substantially rectangularly shaped box having four top corners and four, bottom corners. A standard corner casting is located in each of the corners. Extending rearwardly of said container is a frame supporting a pair of wheels that extend downwardly below the level of the bottom wall. A front support frame extends forwardly of the front wall and supports a downwardly facing pin and bearing plate that are adapted to be engaged by the fifth wheel of a tractor truck. As a result of this construction, one trailer can be stacked directly on top of another without interference by the wheels or bearing plate and pin. The two stacked trailers can be secured together by the use of the mating corner castings.